Overedge stitch forming mechanism



Aug. 15, I

OVEREDGE STITCH FORMING MECHANISM Filed Dec. 9, 1929 3 Sheets-Sheet 1Aug. 15, F T 1,922,966

OVEREDGE STITCH FORMING MECHANISM Filed Dec. 9, 1929 3 Sheets-Sheet 2Aug. 15, 1933- T 1,922,966

OVEREDGE STITCH FORMING MECHANISM Filed Dec. 9, 1929 3 Sheets-Sheet 3nism for sewing machines for forming overedge the looper thread 1001? ad presents its Own 1 1 Patented Aug. 15, 19333 UNITED STATES PATENTOFFICE.

1,922,968 OVEREDGE STITCH FORMlNG MECHANISM Friedrich Lutz, Stuttgart,Germany, assignor to Union Special Machinenfabrik, G. in. b. H.,Stuttgart, Germany Application December 9, 192.9,Serial No. 412,792,

and in Germany January 9, 1929 -1 Claim. (01. 112-462) The inventionrelates to new and useful imported so that it may be shifted for varyingthe provements in stitch forming mechanisms for oscillating position ofthe overedge looper. The sewing machines, and more particularly to anbracket has its supporting base curved about an overedge stitch formingmechanism. axial line and the machine frame is provided with It is Wellknown that in an overedge stitch a similarly curved supporting seat forthe forming mechanism including a needle. a looper bracket. beneath thework support and a looper operating Suitable bolts are provided forholding the. over the edge of the work support that said overbracket invarious set positions. The curvature edge looper should move in rear ofthe under of this supporting face of the bracket is such looper and infront of the needle in order to that. when the working position of thelooper is make a proper stitch formation. It is also well shifted, theplane of oscillation of the looper will known that in order to avoid theskipping of be changed so as to produce a greater or less stitches thelooper should work close to the neeangle with the plane of the worksupport and dle as it passes the same. thus it is that the looper whenshifted can be An object of the present invention is to proset so as topass properly in rear of the lower vide a supporting means for theoveredge looper looper and also pass properly in front of the wherebythe working position of the looper may needle. i be shifted so as toproperly position the looper When the needle is changed from a smallerfor needles of different diameters. to a larger needle, then the looperbracket is In the drawings which show by way of i1lusshifted so that theoveredge looper will clear the tration one embodiment of the invention:needle when above the work support and at the Figure l is a view fromthe front of the machine same time move close to the needle so as toshowing the improved supporting means for the insure proper stitchformation. v e ooper. The invention will best be understood by a Fig. 2is a View showing the supporting means more detailed reference to thedrawings wherefor the overedge looper in side elevation and also in theoveredge looper is indicated at 1. This showing the position of theunder looper. overedge looper is mounted on a carrier 2 which Fig. 3 isa plan view of a part of a sewing mais attached to a shaft 3 and theshaft 3 is mounted chine showing the means for supporting the overforoscillation in a bracket 4. A link 5 is conedge looper. nected to an armprojecting from a sleeve at- Fig. 4 is a view showing more or lessdiagramtached to the shaft and thus it is that the shaft matically theneedle, the needle path and the is oscillated and the overedge loopermoved from plane in which the overedge looper oscillates. a positionbeneath the plane Of the W up- Fig. 5 is a view similar to Fig. 4, butshowing port to a position over the plane of the work supthe overedgelooper shifted so as to change the Do e needle is indicated at 6 in thedraW- inclination of its path of oscillation for a different ings. Theun o p is indicated at 21 n the size needle. drawings. This under looperis preferably of a Fig. 6 is a view in perspective showing more threadcarrying type and moves into the needle or less diagrammatically theneedle, the under t ad 1001) beneath e w upp a d' a looper, and theoveredge looper at the extremes p n Wh e h v r s l p r engages said ofits movement, and the 10 9331 d curvalooper thread and carries the sameabove the ture of the bracket supporting th overedge work support sothat it is positioned for the needle looper. to enter the same. If theoveredge looper is of The invention is directed to a stitching mechaathread carrying t p n of u i nt rs stitches, which includes areciprocating needle, fill the needle entelfi This yp 0f V d an underthread carrying loo er, d an Overstitch forming mechanism is well knownin the edge looper. The overedge looper is mou t d t art. The feedingmechanism is not shown in the oscillate about a fixed axis which is sodisposed dalwirlgsi but the 11R3 of feed intelsecfis the that the loopermoves in a plane inclined to the needle P Substantially at the point 16,and is work support and passes from a position in rear in a dir-pctioilat right angles the plane of Q of the under looper beneath the clothplate to per or directly aw VfIOm the Observer, in a position in frontof the needle above the cloth Figures 1 and plate. The shaft supportingthe upper looper The present invention is directed particularly 110 ismounted in a bracket which is in turn suptothe way in which thebracketsupporting the overedge looper is mounted whereby the oscillatingposition of the looper may be changed at will.

The supporting bracket 4 for the looper is provided with a curvedcylindrical face 8. The

frame 13 of the machine is provided with a simline of the shaft 3carrying the overedge looper 1 at 11. The overedge looper 1 moves froma. point 19 beneath the work support to a point 18 above the worksupport. The path of movement of the looper is indicated by line 15,Fig. 6. The axial line 16 of the cylindrical faces 8 and 9 alsointersects the path of movement of the looper at the point 17. The axisof the looper shaft is inclined to the axial line 16, as has alreadybeen noted.

When the bracket 4 is shifted, it isshifted about the axial line 16, andinasmuchas this line intersects the path of oscillation of the overedgelooper midway as indicated at 1 between the extremes of movement of thelooper, this point remains substantially the same for various set set soas to. move in the path indicated at 1a-1a for a given size of needle 6.When it is desired to use a larger needle as indicated at '7 in Fig.

5, then the bracket is shifted, and when the bracket is shifted, theplane of oscillation of the looper is charged so that the looper movesto a greater extent in rear of the under looper and a greater extent infront of the needle, as clearly shown in Fig. 5. The looper will,however, always pass through the point 1'? regardless of the setposition of the bracket 4.

A loop holder is indicated at 20 in the drawings. This loop holder is inline with the axis of the'shaft supporting the overedge looper andmounted on the bracket 4 so that when the bracket 4 is shifted this loopholder will also be shifted. I V a From the above it will be apparentthat a sup port for the overedge looper has been provided which whenshifted changes the angle of the plane of oscillation of the looperrelative to the work support and thereby the overedge looper may becaused to move at different distances from the center of the needle pathwithout interfering with its proper cooperation with the under looper.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent, is:-

In an overedge stitch forming mechanism, the combination of a needle, anunder looper. an overed'ge looper, a shaft on which said over edgelooper" is mounted for oscillation, a

bracket for supporting said shaft, said shaft being disposed so that thelooper moves in a path passing in rear of the under looper and in frontof the needle, and a frame member for justably supporting said bracket,said bracket and frame member having their contacting faces curved aboutan axial line passing through the axial line ofoscillation of theoveredge looper and a joint in the path of movement of the loop ermidway between the extremes of movement of said overedge looper.

- FRIEDRICH LUTZ.

